Disinfection Byproducts, Oxidative Stress, and Sleep Quality among Healthy Chinese Men

Toxicological studies show that disinfection byproducts (DBPs) adversely affect neurological and psychiatric symptoms, which have been linked to poor sleep quality. This cohort study explored the associations between DBP exposure, oxidative stress, and sleep quality assessed by the Pittsburgh Sleep Quality Index (PSQI) questionnaire among young healthy Chinese men who provided 710 blood and 2647 repeated urinary samples over 3 months. We measured trihalomethanes in blood and haloacetic acids and oxidative stress markers in urine samples. In adjusted models, each 2.7-fold increase in urinary trichloroacetic acid (TCAA) concentrations was associated with a greater PSQI score of 0.29 (95% confidence interval: 0.07, 0.50). A clear dose-response relationship was observed when TCAA concentrations were included as quartile variables (P for trend = 0.01). In the analyses of individual PSQI components, TCAA was associated with a greater risk of difficulty in falling asleep, short sleep duration, and daytime dysfunction (odds ratios = 1.33 (1.04, 1.70), 1.35 (1.03, 1.78), and 1.39 (1.08, 1.78), respectively, per 2.7-fold increase in TCAA concentrations). Mediation analyses showed that 4-hydroxy-2-nonenal-mercapturic acid mediated 22.24% (4.44%, 80.00%) of the association between TCAA concentrations and PSQI scores. In summary, TCAA exposure may affect sleep quality, which is partly mediated by oxidative stress.